1. Field of the Invention
The present invention is directed to surface cleaning equipment, and more particularly to a squeegee linkage for surface cleaning equipment.
2. Description of the Related Art
Surface maintenance vehicles and cleaning devices have a long history subject to gradual innovation and improvement toward improved and oftentimes automated performance in removing debris and contamination from floors. These vehicles and devices may be self-powered, towed, or pushed, and/or manually powered and may carry a human operator during cleaning operations. Such vehicles and devices include scrubbers, extractors, sweepers and vacuums, as well as combinations thereof, intended for cleaning, scrubbing, wiping and/or drying a portion of a substantially flat surface both indoors and outdoors. Many such vehicles and devices employ a squeegee assembly for wiping dry a floor which has been cleaned by application of a cleaning solution of water and a detergent in conjunction with scrubbing action of one or more moving brushes. Accordingly, the squeegee assembly of such prior art cleaning vehicles often mounts at or near the rear of the surface maintenance vehicle to direct the solution to a removal location where the solution (including suspended dirt, particles and contaminants) is removed. In this disclosure, the term “loaded cleaning solution” shall apply to such a cleaning solution after application thereof to a floor or other surface to be cleaned. The cleaning solution is typically supplied to the floor surface through or near rotary scrub brushes operating from a lower portion of the vehicle. The squeegee assembly may include a squeegee supporting member with a squeegee blade affixed to the supporting member to promote consistent contact with the surface to be cleaned and wiped. Alternately, the squeegee assembly may include more than one squeegee blade.
The squeegee blade and squeegee supporting member are attached to the frame of the vehicle by a squeegee linkage. Often the squeegee is a trailing type, used to collect any fluids which get past the cleaning/treating apparatus and provide a way to do a final clean up. This technology is applicable however to a leading or side retractable collector/surface treatment element (including a squeegee) and the claims should be interpreted as such. As the vehicle moves to clean a portion of a floor, the squeegee linkage should generally provide a constant downward force on the squeegee blade so that the blade remains uniformly engaged with the floor. In addition, the squeegee linkage should be able to retract the squeegee blade when the vehicle moves without cleaning, so that the blade does not damage the floor. Further, because the squeegee blade may protrude beyond the extent of the vehicle wheels, and the operator may inadvertently knock the blade into an immovable object, the squeegee linkage should be able to sustain a side impact without damage.
A prior art squeegee linkage, known as a “four bar” linkage, is used in a rider vehicle, model 7100, commercially available from the Tennant Company. In the four bar linkage, two parallel rods, horizontally spaced apart, are vertically pivotably attached to the frame of the vehicle at their first ends, and are vertically pivotably attached to the squeegee supporting member at their second ends, so that the squeegee supporting member may translate in the vertical direction. Additionally, two more parallel rods, located vertically adjacent to the first two rods, are similarly fastened to both the vehicle frame and the squeegee support member, so that when the squeegee supporting member translates, it maintains its angular orientation with respect to the vehicle frame. A tension spring provides a downward force on the squeegee supporting member, and an actuator is capable of raising the squeegee supporting member when required. The four bar linkage is relatively complicated, is relatively expensive, requires frequent adjustments, and provides relatively little shock absorption against horizontal impacts. Furthermore, if the actuator is damaged, a significant effort is required to access and replace the damaged part. A variation of the four bar linkage uses spherical rod bearings, which also provide for limited rotation in the horizontal plane. This allows for some side-to-side motion of the squeegee (such as under impact), but it also requires centering springs to consistently return the squeegee to its normal operating position, and spherical rod bearings add significantly to the cost of the system.
Another prior art squeegee linkage, known as a “pivoting plate” linkage, is used in a walk-behind vehicle, model 5400, also commercially available from the Tennant Company. The entire linkage is located on one side of a horizontal pin, and may be raised and lowered by an actuator by pivoting about the horizontal pin. Adjacent to the horizontal pin is a plate, which may pivot vertically about the horizontal pin, but has no horizontal adjustments. The plate is slidably fastened to a chuck at two locations—at a fixed slot, about which the chuck may pivot horizontally with respect to the plate, and at a pin, which freely slides horizontally along a generally horizontal slot located in the plate. The plate and the chuck move vertically as one unit, so that the entire linkage may be raised and lowered by an actuator. Because the pivoting plate linkage is designed for a walk-behind vehicle, in which the steering is done primarily from the rear wheels, the linkage is designed to swing freely from side-to-side, in order to ensure that the loaded solution is properly picked up during turns of the vehicle. This side-to-side motion is typically not required from a rider vehicle, in which the steering is generally done from the front wheels. Although simpler than the four bar linkage, the pivoting plate linkage is complicated, is fairly expensive, and provides only limited shock absorption. Likewise, if the actuator is damaged, a significant effort is required to access and replace the damaged part.
Accordingly, there is a need for a simplified (and therefore less expensive) squeegee linkage, with improved shock absorption, and with a quick release mechanism that improves access to a potentially damaged actuator.